GFCI's

[Don Y]

The outlets in the back of the house are on a 20A GFCI.
(Note to self: are there any other outlets on that same
circuit that I need to chase down?)

Presently using them to light XMAS lights on one of the
citrus trees. IIRC, each string is about 250W. With
~700W on the circuit, turning the breaker ON (i.e., using
it as a switch -- instead of plugging/unplugging the
load) causes it to immediately trip. Repeating the
action in short order appears to get it to latch and
remain latched (ON), indefinitely.

OK, so the surge when all the lamps are cold can increase
the inrush current -- on the short term -- to levels that
probably exceed the 20A limit of the breaker.

"In theory"

OTOH, in years past, I've run the circuit at close to its
capacity (~10 strings) without this problem.

I've changed breakers (swapped with one feeding another
circuit) and the problem persists.

[There are no leakage paths in the wiring OUTSIDE]

This suggests something in the wiring/fixtures. I'll
start isolating outlets, tomorrow (dark here, now).
Perhaps some insect (leaf cutter?) has opted to nest
in one of the receptacles.

Anything else I should explore?

[Don Y]

On 12/1/2015 7:19 PM, Don Y wrote:
> The outlets in the back of the house are on a 20A GFCI.

For those who didn't connect the dots, this is a GFCI *breaker*,
not a GFCI *outlet* daisy-chained to feed the others.

[cl...@snyder.on.ca]

Does it trip with nothing connected? If not, it's not a dauber or
anything on the main circuit. It has to be on the "load". Outdoor
lights on a GFCI can be a problem - lots of possibilities for
"leakage"

[gfre...@aol.com]

Since you are swapping stuff around, try it on a non-GFI circuit. That
will tell you if it is a ground fault.
Usually this tracks back to water/bugs in a box.

I have one nightmare GFI circuit here that is longer than the design
spec for GFIs but it works when everything is dry. When it fails, I
end up splitting the circuit up to isolate the failure. Bear in mind,
it can be a ground fault on the neutral.
On outside boxes, make sure all of the wirenuts are pointed up, near
the top of the box and that they are not too close to the box. It
mitigates the water they all collect eventually.

[gfre...@aol.com]

If there is absolutely nothing connected, a neutral fault will not
trip the GFCI. The slightest load will trip it tho. (it splits the
neutral current)
The other thing to remember is the faults are additive. If you are
leaking a couple ma in a couple places, it will work until the total
gets up around 5ma or so.

[Don Y]

On 12/1/2015 7:46 PM, cl...@snyder.on.ca wrote:
> On Tue, 01 Dec 2015 19:26:18 -0700, Don Y
> <blocked...@foo.invalid> wrote:
>
>> On 12/1/2015 7:19 PM, Don Y wrote:
>>> The outlets in the back of the house are on a 20A GFCI.
>>
>> For those who didn't connect the dots, this is a GFCI *breaker*,
>> not a GFCI *outlet* daisy-chained to feed the others.
> Does it trip with nothing connected?

Appears not to. OTOH, it won't trip with smaller loads.

> If not, it's not a dauber or
> anything on the main circuit. It has to be on the "load". Outdoor
> lights on a GFCI can be a problem - lots of possibilities for
> "leakage"

The problem is, I can't tell if it is tripping from a momentary
"over current" condition *or* a "leak". The fact that the
circuit *holds* on the second attempt suggests it is related to
the turn on transient (all those ice cold filaments now having
had a chance to warm up -- even only momentarily -- to higher
operating resistances).

Note that the other GFCI breakers have operated flawlessly for
exactly the same length of time -- with more frequent usage
(the outdoor circuit is rarely used) located in the same
(outdoor) electrical panel. That, coupled with swapping breakers
suggests the problem isn't in the breaker (or panel).

I'll try moving the load to a different receptacle and isolating this
portion of the branch circuit. That will require a "longer" extension
cord (actually, the current cord is long enough; I'll just have to
unwind it from its "storage spool") so I will first verify the
"bad" outlet fails with that lengthened cord before trying the
lengthened cord in an upstream outlet.

[Micky]

On Tue, 01 Dec 2015 19:19:01 -0700, Don Y
<blocked...@foo.invalid> wrote:

>The outlets in the back of the house are on a 20A GFCI.
>(Note to self: are there any other outlets on that same
>circuit that I need to chase down?)

My 1979 house near Baltimore was built with one GFCI circuit that
powers the front outdoor receptacle, the recepts in each bathroom, and
iirc the one near the sink in the kitchen.

I bought the house when it was 4 years old, and within a couple years,
the breaker kept tripping, but the replacement has only tripped twice
in 30 years.

For the last 12 years I've had a heavy orange extension cord plugged
into the front outdoor outlet, or into an extension cord plugged into
it. The female end of both has lain in the grass for the last 12
years, 365 days a year/24, through rain and snow and sleet and gloom
of night. And the breaker has only tripped twice. Many different
locations, wherever I feel like throwing it at the end of the day.

I do make a point to pick it up a foot from the end when it's wet.

>Presently using them to light XMAS lights on one of the
>citrus trees. IIRC, each string is about 250W. With
>~700W on the circuit, turning the breaker ON (i.e., using

I use a B&D elelctric lawnmower with no problem, but i don't know its
rating or other things about your question.

[gfre...@aol.com]

On Tue, 01 Dec 2015 20:25:06 -0700, Don Y
<blocked...@foo.invalid> wrote:

> I'll just have to
>unwind it from its "storage spool")

Try just unwinding it from the spool and trying it again. You may just
be coupling current into the grounding conductor.

Because of that, they do have specs for different wiring methods and
the total length of the circuit.

[Don Y]

You're ignoring the fact that the breaker latches and HOLDS on the
"second attempt". This suggests the problem is related to the
change in load characteristics from the previous "brief lighting
event" (fraction of a second when power surged into the lamps
just before the breaker trips on the first attempt).

I'm at a loss to explain how anything else could appear and
then disappear so readily!

[Don Y]

Again, nothing changes on the spool between the first breaker closure
(that trips) and the second (that holds).

Same extension cord used in previous years. Tree is in the same location
that it was -- as is the electrical outlet (i.e., so, no more or less
cord on the reel than in past years). Same strings of lights (though far
FEWER of them). Same ambient temperatures. etc.

I'll have to play with it some more to get a better characterization
of how it behaves (different size loads, different TYPES of loads, how
long the circuit needs to "rest" before the problem will reproduce, etc.)

[Don Y]

Moving the strins of lights to another circuit would take the
existing wiring *and* GFCI out of the calculus.

OTOH, I could see if there's a breaker nearby that I can
"borrow" onto which to move the existing wiring. I.e.,
I've tried changing JUST the GFCI breaker with another
GFCI breaker (keeping everything else constant); this would
allow me to try nonGFCI vs. GFCI (again, keeping everything
else constant).

Trick will be to see how far I can reach in the electric panel
to pick up a different breaker.

> Usually this tracks back to water/bugs in a box.

Boxes are recessed into block/cement walls. Faces sealed with
foam gaskets. Outdoor "in use" covers keep out direct rain/water.

Bugs, OTOH, can always crawl in through the hole in the cover intended
for the cords to exit.

But, bug would lead to suspected GFCI issue. And, would persist
(not "clear" itself after the first breaker trip/reset)

> I have one nightmare GFI circuit here that is longer than the design
> spec for GFIs but it works when everything is dry. When it fails, I
> end up splitting the circuit up to isolate the failure. Bear in mind,
> it can be a ground fault on the neutral.

Again, see above. IMO, it has something to do with the initial
transient. I need to find a load that is more PURELY resistive
to see what it's like when the load is X from the moment the
breaker is FIRST closed.

[Paint...@unlisted.moc]

On Tue, 01 Dec 2015 19:19:01 -0700, Don Y <blocked...@foo.invalid>
wrote:

>The outlets in the back of the house are on a 20A GFCI.
>(Note to self: are there any other outlets on that same
>circuit that I need to chase down?)
>
>Presently using them to light XMAS lights on one of the
>citrus trees. IIRC, each string is about 250W. With
>~700W on the circuit, turning the breaker ON (i.e., using
>it as a switch -- instead of plugging/unplugging the
>load) causes it to immediately trip. Repeating the
>action in short order appears to get it to latch and
>remain latched (ON), indefinitely.
>

What are yiou using for lights? It sounds like they are incandescent C9
bulbs in strings of 25 bulbs. (which is actually 225Watts). [25 times
9watts].

>OK, so the surge when all the lamps are cold can increase
>the inrush current -- on the short term -- to levels that
>probably exceed the 20A limit of the breaker.
>

700W is not even close to 20A.
A 20A breaker can handle roughly 2400 watts.
(Of course you dont want to run it at it's maximum load).
Either way, 700W is only around 30% of the capacity of the breaker.
Yea, starting current is always higher, but even if it was double (1400)
watts, you're still way below the allowable load limit for a 20A
circuit.

>"In theory"
>
>OTOH, in years past, I've run the circuit at close to its
>capacity (~10 strings) without this problem.
>
>I've changed breakers (swapped with one feeding another
>circuit) and the problem persists.
>
>[There are no leakage paths in the wiring OUTSIDE]
>
>This suggests something in the wiring/fixtures. I'll
>start isolating outlets, tomorrow (dark here, now).
>Perhaps some insect (leaf cutter?) has opted to nest
>in one of the receptacles.
>
>Anything else I should explore?

Check, check twice, check 3 times and check again for any minor breaks
in the light strings. One very tiny spot of bare wire, a bulb base
slightly exposed and touching a tree branch, or the soil, and so on....
Christmas light strings are notorious for electrical leakage and if
they're old, even more so.

Also, years ago, when I used to decorate outside of my parents house,
using those C9 (and C7) strings, more than once one of the bulbs seemed
to develop an internal short. Apparently the filament broke, but welded
itself back together but it was shorter and drew excess current. That
bulb would eventually burn out, but sometimes it would blow a fuse when
it died.

So, you might check every bulb for any sign of defect, which is easier
said than done. Or replace all the bulbs in one string at a time.

Better yet, just buy some C9 sized LED strings, and if you have them on
every night until the end of December, they will probably pay for
themselves in electrical savings. Just a guess, but a string of 25 LEDs
probably use about 20 to 30 watts.

Three strings of incandescent will use 675W (Roughly 700W) every hour.
So whatever you pay per KWH, is spent approximately every 1-1/2 hours.

As an example, if you pay 15 cents per KWH, Six hours per day will cost
you 60 cents per night. That's a cost of $18 for one month.

Three LED strings will use around 80W per hour. 480W in 6 hours, which
amounts to about 7 cents per day or $2.10 for an entire month.

You save $15.90 in that month.

[cl...@snyder.on.ca]

On Wed, 02 Dec 2015 00:13:36 -0700, Don Y

Unless the first application of power heated and "dried" whatever
was causing the leak. Not a very likely scenario, for sure - but
possibly just within the realm of possibility??

[cl...@snyder.on.ca]

On Wed, 02 Dec 2015 00:25:12 -0700, Don Y

Make up a "soft start box" getr an electric heater. take a short
extension cord (or make one uo) and cut the live wire, inserting a
second plug in series with the existing one. Plug the heater into the
second plug, the lights into the first. This will reduce the current
on startup. Wire a switch across the second plug so you can short the
heater out of the circuit after the lights come on. This will tell you
for sure if it is a cold surge problem. If you get a 750/1500 heater
you can select how hard or soft the start is.

[cl...@snyder.on.ca]

But the current spike on LEDs can be pretty healthy too- depending
what kind of driver circuit. Just a series string, not so much - but
LED drivers? OUCH!!

[Don Y]

On 12/2/2015 5:29 AM, cl...@snyder.on.ca wrote:

>> You're ignoring the fact that the breaker latches and HOLDS on the
>> "second attempt". This suggests the problem is related to the
>> change in load characteristics from the previous "brief lighting
>> event" (fraction of a second when power surged into the lamps
>> just before the breaker trips on the first attempt).
>>
>> I'm at a loss to explain how anything else could appear and
>> then disappear so readily!
> Unless the first application of power heated and "dried" whatever
> was causing the leak. Not a very likely scenario, for sure - but
> possibly just within the realm of possibility??

<frown> I'm at a loss. If there was a "partial short" (leak) that
somehow cleared itself, then I wouldn't expect it to return hours
later -- and the same scenario play out again. And, again.

I need to get out a watch and see how long I can wait *after* the
first breaker close before the *next* closing will NOT hold.
I.e., how long it takes the "problem" to reappear.

It it's on the order of a few minutes, it's unlikely that there's a
"partial short" (dead bug, etc.).

Note that this is a dry time of year for us -- it's not like there
are any external (or internal!) sources of water/moisture (other
than body fluids of bugs :> )

[Don Y]

On 12/2/2015 5:36 AM, cl...@snyder.on.ca wrote:

> Make up a "soft start box" getr an electric heater. take a short
> extension cord (or make one uo) and cut the live wire, inserting a
> second plug in series with the existing one. Plug the heater into the
> second plug, the lights into the first. This will reduce the current

"plug" --> "outlet"

> on startup. Wire a switch across the second plug so you can short the
> heater out of the circuit after the lights come on. This will tell you
> for sure if it is a cold surge problem. If you get a 750/1500 heater
> you can select how hard or soft the start is.

Given that the load is so light, I can use an electric hair dryer
and fiddle with the temp setting (cold/warm/hot/blistering) to
gradually increase the effective load. A switch shunting the hair
dryer's connection to remove it completely.

It's worth a try. I'm going to gather more data, first, so I know
exactly how I can reproduce the problem (e.g., if I have to wait
2 hours for the "short" to redevelop, then any tests more frequent
than that would be foolish.

[mako...@yahoo.com]

So there are 3 strings of lights?

Try switching the breaker on with 2 out of 3 strings plugged in, i.e one string unplugged..

THen change to another 2 out of 3 etc i.e another one unplugged.

If it still trips with 2/3 , it's leakage.
If it doesn't, it's surge current.

[bob haller]

install a regular switch or a timer after the breaker.

not only more convenient, but long term using a breaker as a switch can lead to breaker failure.

[Don Y]

On 12/2/2015 7:36 AM, mako...@yahoo.com wrote:
> So there are 3 strings of lights?

There are three strings "in series" (this is a misnomer; they are obviously
WIRED in parallel, but, each string plugs into the string "upstream" from
it. I.e., the first two strings act as an "extension cord" for the third;
the first string acts as an extension for the second and third; etc.

> Try switching the breaker on with 2 out of 3 strings plugged in, i.e one
> string unplugged..
>
> THen change to another 2 out of 3 etc i.e another one unplugged.
>
> If it still trips with 2/3 , it's leakage.
> If it doesn't, it's surge current.

Note my comment that, in years past, we would have up to 10 (effectively)
strings on the same *single* outlet. E.g., extension cord would run to the
base of the tree. There, a "cube tap" made 3 receptacles available from the
ONE that is present on the extension cord. Two strings were plugged into
that cube tap. Two *more* strings were plugged into the "ends" of each of
these first two strings. And, two more plugged into the ends of each
of those.

So, "two strings of three". Each string has 25 (?) 9W (nominal) lamps
so ~225W/string or 675W per string-of-3; 1350W for the pair of these.

The third outlet on the cube tap would either feed a (65W?) flood light
sited beneath the tree (again, the goal is to cause convective air
currents from the *heat* generated by the lamps -- incandescent lamps
being notoriously inefficient at generating VISIBLE light).

Another extension cord would run from the other half of the same duplex
receptacle off to another tree -- with a set of 3 strings, there.

Or, variations on that theme.

I.e., we would typically be pushing the 20A circuit as far as we could
with a "static" load.

As there's no "switch" to turn these on and off, it's easiest to just
flip the breaker for that circuit (there's nothing else on it). So,
we would turn the breaker on each (late) evening and off each (early)
morning -- in much the same way you'd turn lights on and off in a house.

*We* have "changed" nothing. Yet, something *has* changed. We're not
seeing extraordinarily cold weather (hovering around 30F, recent nights)
whereas we've seen high teens in years past.

It's not raining -- whereas we've had the lights ON in rainy weather,
previously (hence the use of the GFCI -- lest we dance the "electric
bugaloo" when we step outside!)

The house is masonry construction so doesn't "move" to affect the wiring
in any way. Outlets recessed into the block walls so not directly exposed
to the elements.

<frown>

It would be silly to add more strings just to prove it can't handle
an even BIGGER load...

[Don Y]

The first "test" I did was to replace the breaker -- with one that has seen
*no* use.

So, while flipping the breaker on and off a few dozen times a year *may*
fatigue the mechanism, it's not the cause of our current problem (unless
the replacement breaker happens to be defective from the factory).

[gfre...@aol.com]

On Wed, 02 Dec 2015 00:13:36 -0700, Don Y

If it is a clump of moist material, you may be cooking the moisture
out a little with the first attempt. I am not a fan of the "inrush"
theory of GFCI tripping. (or most other myths about what trips them)
This is a simple comparison of the current between the hot and the
neutral through a buck wound transformer. If you really think it is an
overcurrent situation, plug it into a non GFCI circuit to test it

[gfre...@aol.com]

I have lots of GFCIs around here and it is not unusual to have one
that tripped to hold after resetting a time or two.
In the end, I always find a fault somewhere, usually something that is
getting wet.

[gfre...@aol.com]

What happens if the breaker is already on and you just plug in the
lights?

[Don Y]

The breaker trips. This is one of my least favorite ways of testing
as it means a trip all the way around the house to reset the
breaker... By contrast, turning the breaker on with load attached
gives me the same feedback -- and, I'm right there, ready to turn it
back on, again.

On grumbling about this ("yet another chore on my list") to SWMBO,
she claims she took the toaster oven outdoors some months ago
(WTF?) to "prepare" something and it wouldn't work, either.

I.e., that removes the extension cord and lights from the calculus.

I've removed the breaker from the scenario.

I can (with a bit of work) remove individual duplex receptacles
(leaving the balance of the wiring intact) on the theory that
something is *inside* one of these (leaf cutter, etc.).

[I've started doing this hit-or-miss but need to do so in a
more methodical manner so I can draw conclusions from the
observations]

I can (with a lot *more* work) isolate sections of the wiring
(hard to imagine that being an issue -- it's not routed anywhere
that is likely to see abuse, infestation, moisture, etc.)

I will notice how quickly the problem reappears when I turn
the lights off a bit later this morning -- bulbs having been
lit all night (warm filaments, warm lamp bodies, etc.)

[trader_4]

+1

I also don't think the inrush current on 700W on lights could trip
a 20A breaker. If it could, seems we'd have that problem all the
time. 700W is only 6A worth of lights. I would think it's more
likely something related to a fault, but why it would not happen on
the second attempt, IDK.

[Stormin Mormon]

On 12/2/2015 11:02 AM, Don Y wrote:
> On 12/2/2015 8:39 AM, gfre...@aol.com wrote:
>> What happens if the breaker is already on and you just plug in the
>> lights?
>
> The breaker trips. This is one of my least favorite ways of testing
> as it means a trip all the way around the house to reset the
> breaker... By contrast, turning the breaker on with load attached
> gives me the same feedback -- and, I'm right there, ready to turn it
> back on, again.
>

I'm remembering the customer who called. The furnace
tripped the breaker. So, she reset the breaker a
couple dozen times, till the breaker stayed on.
Still won't work.

I find the first problem was a $65 shorted blower
motor. Second problem was the $250 circuit board
that fried cause she kept sending power surges
through it.

--
.
Christopher A. Young
learn more about Jesus
. www.lds.org
.
.

[Don Y]

Then, what is "rehydrating" the material for the *next* time it
trips? No rain, here. Low humidity. No plumbing anywhere
nearby.

> I am not a fan of the "inrush"
> theory of GFCI tripping. (or most other myths about what trips them)
> This is a simple comparison of the current between the hot and the
> neutral through a buck wound transformer. If you really think it is an
> overcurrent situation, plug it into a non GFCI circuit to test it

That assumes the overload characteristics of the non-GFCI breaker
are identical to that of the GFCI breaker. I have yet to find any
documentation that calls out specifics -- for the GFCI breaker *or*
the non-GFCI breakers located in the same panel!

[Don Y]

This can't be the problem. Lights have been on all night.
"Unplugged" them (i.e., don't muck with the breaker).

Wait *1* second and plug in, again. Lights come back on
(i.e., breaker does not trip).

After a few seconds, unplug again. Wait 10 seconds and
plug back in. Again, lights come on.

After a few seconds, unplug a third time. Wait 2 *minutes*
and plug back in. Breaker immediately trips.

[Don Y]

And, plugging the extension cord into a non-GFCI (inside the home)
outlet -- keeping exactly the same amount of cord "wound" on
it's spool as before -- does NOT trip *that* breaker.

I.e., the only thing that has been isolated as a result of these
tests is the wire inside the walls and the actual receptacles;
when that stuff is "in circuit", the breaker trips (either
when turned on *or* when a "cold" load is plugged into it)

I'll try to remove all of the OTHER receptacles (places where
things can infiltrate the wiring) and repeat the original test.

Then, replace the receptacle in question.

Then, move the load to a different receptacle.

Beyond that, I'll have to start opening wire nuts -- not something
I like doing with #12AWG :<

[dpb]

On 12/02/2015 12:08 PM, Don Y wrote:
...

> This can't be the problem. Lights have been on all night.
> "Unplugged" them (i.e., don't muck with the breaker).
>
> Wait *1* second and plug in, again. Lights come back on
> (i.e., breaker does not trip).
>
> After a few seconds, unplug again. Wait 10 seconds and
> plug back in. Again, lights come on.
>
> After a few seconds, unplug a third time. Wait 2 *minutes*
> and plug back in. Breaker immediately trips.

That's got to be a thermal problem in (probably) a particular
lamp...eventually it'll burn out and let you isolate it or the base
itself will fail.

--

[Don Y]

On 12/2/2015 11:54 AM, dpb wrote:
> On 12/02/2015 12:08 PM, Don Y wrote:

> ....

Unplug the three strings from the extension cord. Leave cord
exactly as is. Take three *other* "identical" strings out
and wire them in exactly the same fashion as the first set-of-three.

Turn on breaker. Trips immediately. Let it reset and turn it
on a second time. Holds.

Walk around house to return to the point where the extension cord
is plugged in.

Unplug. Wait a few seconds. Plug back in. Breaker trips.

(No, I'm not going to keep repeating this test to see how long
it takes for the load to "deteriorate" between power applications.
The fact that it tripped suggests the problem is not in the
original three strings of lights -- or, coincidentally ALSO
happens to be in the OTHER three strings, as well. And, no, I'm
not going to drag out a third set of three... or a fourth
set of three... :> )

[dpb]

On 12/02/2015 1:08 PM, Don Y wrote:
> On 12/2/2015 11:54 AM, dpb wrote:

...

>> That's got to be a thermal problem in (probably) a particular
>> lamp...eventually
>> it'll burn out and let you isolate it or the base itself will fail.
>
> Unplug the three strings from the extension cord. Leave cord
> exactly as is. Take three *other* "identical" strings out
> and wire them in exactly the same fashion as the first set-of-three.
>
> Turn on breaker. Trips immediately. Let it reset and turn it
> on a second time. Holds.
>
> Walk around house to return to the point where the extension cord
> is plugged in.
>
> Unplug. Wait a few seconds. Plug back in. Breaker trips.
>

...

Hadn't seen the duplicated test result...

I'd stick with the thermal issue and I'd suspect the cord if it's one of
those w/ the indicator lamp built into the plug.

Did you ever isolate whether there were any other loads on this circuit
besides these two (I think were mentioned early on?) exterior receptacles?

--

[mako...@yahoo.com]

Seems that the surge current of all those bulbs is just a bit too high for the breaker.


So here's a question...

I assume the lights in question are small incandescent bulbs.

Are they the type that you can unscrew one and all the other bulbs stay lit (indicating they are wired in parallel) or are they the tiny bulbs that if you unplug one bulb many others in the string go out as well (indicating that they are wired in series)?

Mark

[Don Y]

On 12/2/2015 12:31 PM, dpb wrote:
> On 12/02/2015 1:08 PM, Don Y wrote:
>> On 12/2/2015 11:54 AM, dpb wrote:

> ....

>
>>> That's got to be a thermal problem in (probably) a particular
>>> lamp...eventually
>>> it'll burn out and let you isolate it or the base itself will fail.
>>
>> Unplug the three strings from the extension cord. Leave cord
>> exactly as is. Take three *other* "identical" strings out
>> and wire them in exactly the same fashion as the first set-of-three.
>>
>> Turn on breaker. Trips immediately. Let it reset and turn it
>> on a second time. Holds.
>>
>> Walk around house to return to the point where the extension cord
>> is plugged in.
>>
>> Unplug. Wait a few seconds. Plug back in. Breaker trips.
>>

> ....

>
> Hadn't seen the duplicated test result...
>
> I'd stick with the thermal issue and I'd suspect the cord if it's one of those
> w/ the indicator lamp built into the plug.
>
> Did you ever isolate whether there were any other loads on this circuit besides
> these two (I think were mentioned early on?) exterior receptacles?

The only (intentional!) load on the circuit is these (or "those" -- depending
on whether you refer to the original 3 or the replacement 3) 3 strings of
lamps.

I.e., in a theoretical scheme, it's just a long wire with a bunch (5)
of duplex receptacles hanging off it, fed through a circuit breaker
(which has been replaced with an "unused" GFCI).

The fact that the different strings don't appear to make any difference
to the result *suggests* it's not in the "load".

The fact that a different GFCI doesn't appear to make a difference
tends to rule that out.

This leaves outlets, wiring and extension cord.

The fact that lights plugged into extension cord doesn't cause a
problem on another branch circuit suggests the cord MIGHT not be
a problem (it could still be "leaky" and the non-GFCI doesn't
notice that).

I can remove receptacles from the wiring (a bit of a hassle to
remove the "outdoor" covers, remove the receptacle, then
remove the two conductors -- I can leave the safety ground as
long as I ensure the receptacle is "dangling freely")

Isolating portions of the wiring gets to be a bit more
involved; instead of "daisy chaining" through the second
set of contacts on the receptacles, I tie the upstream and
downstream wiring together with wire nuts and run a pigtail
off to the receptacle. This ensures the receptacle is not
"in series" with the downstream devices.

But, today is shopping day. <frown> So, instead of using the
daylight hours to troubleshoot the problem, I'll waste them
running around buying "stuff". (sigh)

[Don Y]

In the past, there were 3 times as many bulbs in place without a problem!

> So here's a question...
>
> I assume the lights in question are small incandescent bulbs.

IIRC, they are 9W, miniature base.

> Are they the type that you can unscrew one and all the other bulbs stay lit
> (indicating they are wired in parallel) or are they the tiny bulbs that if
> you unplug one bulb many others in the string go out as well (indicating
> that they are wired in series)?

The bulbs are wired in parallel. I.e., the two conductors pass *to*
each socket and continue onward to the end of the string. At that
point, an outlet is located -- which feeds the next string in the
"series" (as in "sequence").

The wire gauge is such that you aren't supposed to daisy-chain
more than two additional strings onto any string in the "series".
Hence the reason we use a cube tap to start a new "set".

Running each string to a single feed point (from the extension
cord) greatly complicates the logistics of getting lamps all the
way around the tree. And, makes the end of the extension cord
a crowded place...

[gfre...@aol.com]

On Wed, 02 Dec 2015 10:56:19 -0700, Don Y

They seem to just be a regular breaker with a GFCI manual trip
mechanism built in.

http://gfretwell.com/electrical/gfci.jpg

[gfre...@aol.com]

On Wed, 02 Dec 2015 11:08:06 -0700, Don Y

You may just have a bad breaker.

[mako...@yahoo.com]

>
> In the past, there were 3 times as many bulbs in place without a problem!
>

wow

so maybe your breakers aged... (I'm serious, they do age)

or you changed extension cords to a heavier guage?

or there is other load in another outlet on the same breaker

I would as a test change to a non GFI breaker to eliminate that possibility.

I didn't see the naswer to the 2 out of 3 question, what if you use 2 strings instead of 3?

Mark

[Don Y]

On 12/2/2015 1:31 PM, mako...@yahoo.com wrote:
>
>>
>> In the past, there were 3 times as many bulbs in place without a problem!
>>
>
> wow
>
> so maybe your breakers aged... (I'm serious, they do age)

5 breakers located "in a row" in the electrical panel.
One has never been wired to anything (that's the breaker that I
used to replace the one in question). The other three are
reliably servicing kitchen counter outlets and bathrooms.
All see regular loads. None have ever tripped (for overload
*or* ground fault)

> or you changed extension cords to a heavier guage?

Same extension cords that have been used in the past.
If this one wasn't actually used on *this* tree LAST
year, then it was used on one of the OTHER trees.

> or there is other load in another outlet on the same breaker

Nope. Only 5 (duplex) outlets. Four of them along the back
of the house, the fifth around the side.

> I would as a test change to a non GFI breaker to eliminate that possibility.

Moving to a non-GFCI *circuit* yields reliable operation.
What I haven't tried is swapping the GFCI breaker with a
nonGFCI breaker. That requires a bit of rewiring and
leaving that other branch circuit idle while testing.

[I'm comfortable working with electricity -- but in the panel,
there's nothing between you and "sudden death" :> I'm not
going to flip the main breaker just to make these sorts
of breaker changes]

> I didn't see the naswer to the 2 out of 3 question, what if you use 2 strings instead of 3?

Should I then move to 1 out of 3? And, from that, 24 out of 25 bulbs?
Then 23 out of 25? etc.

The fact that this is just a MODEST load suggests the problem has to
be noticeable. If I was pulling 2200W, I could imagine some merit
to downsizing the load to 2000W -- or even 1000W! But, at 675W,
my microwave oven draws that! My *hairdryer* draws more than that!

[Don Y]

Did you miss the point where I said I replaced the breaker?
TWO bad breakers? But the other three located within inches
in the panel are all OK? Swap one of those in for the
bad circuit (wanna bet that would be a wasted effort??)

[dpb]

On 12/02/2015 1:59 PM, Don Y wrote:
> On 12/2/2015 12:31 PM, dpb wrote:
>> On 12/02/2015 1:08 PM, Don Y wrote:
>>> On 12/2/2015 11:54 AM, dpb wrote:
>> ....

...

>> ....
>>
>> Hadn't seen the duplicated test result...
>>
>> I'd stick with the thermal issue and I'd suspect the cord if it's
>> one of those w/ the indicator lamp built into the plug.
>>

...

> The fact that the different strings don't appear to make any
> difference to the result *suggests* it's not in the "load".

I just had basically agreed with that assessment...as said, hadn't seen
that diagnostic result previously.

...

> This leaves outlets, wiring and extension cord.
>
> The fact that lights plugged into extension cord doesn't cause a
> problem on another branch circuit suggests the cord MIGHT not be a
> problem (it could still be "leaky" and the non-GFCI doesn't notice
> that).

Precisely; since you later say you have other extension cords
I suggest swapping it out on the same breaker next before doing anything
more involved.

> I can remove receptacles from the wiring (a bit of a hassle to remove
> the "outdoor" covers, remove the receptacle, then remove the two
> conductors -- I can leave the safety ground as long as I ensure the
> receptacle is "dangling freely")
>
> Isolating portions of the wiring gets to be a bit more involved;
> instead of "daisy chaining" through the second set of contacts on the
> receptacles, I tie the upstream and downstream wiring together with
> wire nuts and run a pigtail off to the receptacle. This ensures the
> receptacle is not "in series" with the downstream devices.

...

Any of that starts to seem pretty far-fetched to me albeit almost
anything is possible. OH, just a really far-out thought--you don't have
any of the "crazy ants" there, do you? They can cause all kinds of
really bizzaro thingos/symptoms if they've found a receptacle box and
set up shop...

--

[mako...@yahoo.com]

The fact that this is just a MODEST load suggests the problem has to
be noticeable. If I was pulling 2200W, I could imagine some merit
to downsizing the load to 2000W -- or even 1000W! But, at 675W,
my microwave oven draws that! My *hairdryer* draws more than that!

You do know that incandescent bulbs can pull about
10x the current on turn on?

[Don Y]

Yes. And you'll note that when we were pulling 2000W in previous
years, THE BREAKER NEVER TRIPPED!

(We've been growing oranges for 15+ years)

[gfre...@aol.com]

On Wed, 02 Dec 2015 13:45:31 -0700, Don Y

How much cord do you have out there and is it still on that spool?

I would keep eliminating the various components in this circuit until
you get to what the problem is.

[Don Y]

On 12/2/2015 2:58 PM, dpb wrote:

>> The fact that the different strings don't appear to make any
>> difference to the result *suggests* it's not in the "load".
>
> I just had basically agreed with that assessment...as said, hadn't seen
> that diagnostic result previously.

It could still be a problem with the strings of lights; they have all
seen roughly the same sort of use, over the years. Something that happens
to one lamp in one string could also have happened to another lamp in
another string, etc. With 25 lamps in each string -- plus a plug on
one end and an outlet on the other, that's ~80 places a problem could
infest!

>> This leaves outlets, wiring and extension cord.
>>
>> The fact that lights plugged into extension cord doesn't cause a
>> problem on another branch circuit suggests the cord MIGHT not be a
>> problem (it could still be "leaky" and the non-GFCI doesn't notice
>> that).
>
> Precisely; since you later say you have other extension cords
> I suggest swapping it out on the same breaker next before doing anything more
> involved.

Too late to do anything more, today. I'll just turn the lights on
and deal with it, again, tomorrow (if I have spare time).

>> I can remove receptacles from the wiring (a bit of a hassle to remove
>> the "outdoor" covers, remove the receptacle, then remove the two
>> conductors -- I can leave the safety ground as long as I ensure the
>> receptacle is "dangling freely")
>>
>> Isolating portions of the wiring gets to be a bit more involved;
>> instead of "daisy chaining" through the second set of contacts on the
>> receptacles, I tie the upstream and downstream wiring together with
>> wire nuts and run a pigtail off to the receptacle. This ensures the
>> receptacle is not "in series" with the downstream devices.

> ....

>
> Any of that starts to seem pretty far-fetched to me albeit almost anything is
> possible. OH, just a really far-out thought--you don't have any of the "crazy
> ants" there, do you? They can cause all kinds of really bizzaro
> thingos/symptoms if they've found a receptacle box and set up shop...

We have "leaf cutter wasps (bees?)" that fill little holes with rolled up
pieces of leaves that they use to make their nests.

Other wasps (?) look for little holes to fill with *mud* nests.

And, of course, various little spiders, etc.

It seems like the size of the safety ground hole in an outlet is
what they target. E.g., I have found that if I leave 1/4" irrigation
tuning on the table in the back porch, when I later go to use it, one
(or both!) ends will be neatly plugged with mud.

That's why I think removing the receptacles (starting with those that
aren't currently powering loads) is a quick first step. Easier than
messing around in the panel (I can turn off the breaker and work
on the receptacles without fear of catching a jolt).

[Don Y]

On 12/2/2015 6:36 PM, gfre...@aol.com wrote:

>>> You may just have a bad breaker.
>>
>> Did you miss the point where I said I replaced the breaker?
>> TWO bad breakers? But the other three located within inches
>> in the panel are all OK? Swap one of those in for the
>> bad circuit (wanna bet that would be a wasted effort??)
>
> How much cord do you have out there and is it still on that spool?

The same amount that has been out there and on the spool for the
last ~decade. I can swap to another spool. I can unwind it all.
But, none of those seem like reliable alternatives (do I then
start considering trimming the length of the cord, etc.?)

> I would keep eliminating the various components in this circuit until
> you get to what the problem is.

Well, that's sort of obvious! :> The trick is figuring it out
before trying the last possible option!

[cl...@snyder.on.ca]

On Wed, 02 Dec 2015 10:56:19 -0700, Don Y

What brand panel and breaker?

[cl...@snyder.on.ca]

On Wed, 02 Dec 2015 11:53:14 -0700, Don Y

Not aluminum, by chance??

[cl...@snyder.on.ca]

Get a spare non-gfi breaker. Pop it into the panel in place of the
GFCI and see what happens.

[cl...@snyder.on.ca]

I think you can pretty definitevly rule out tripping from the load of
the lights - cold surge or not.
How old are the light strings? Or the extension cords?

My strong suspicion is you have electrical leagage somewhere - the
lights are shorting to ground (very high resistance), the cord is
leaking to ground (very high resistance) or you have a leakage
somewhere in the house wiring/outlets.

[Don Y]

On 12/2/2015 7:48 PM, cl...@snyder.on.ca wrote:

> Get a spare non-gfi breaker. Pop it into the panel in place of the
> GFCI and see what happens.

Have to open the "main" side in order to run the neutral leg
for that branch circuit over to the "neutrals" tie point.

Nothing is ever "easy"...

[Don Y]

On 12/2/2015 7:45 PM, cl...@snyder.on.ca wrote:
>> Beyond that, I'll have to start opening wire nuts -- not something
>> I like doing with #12AWG :<
> Not aluminum, by chance??

God, no!

[Don Y]

On 12/2/2015 7:35 PM, cl...@snyder.on.ca wrote:

> What brand panel and breaker?

Old CH.

[Don Y]

On 12/2/2015 7:54 PM, cl...@snyder.on.ca wrote:

> I think you can pretty definitevly rule out tripping from the load of
> the lights - cold surge or not.
> How old are the light strings? Or the extension cords?

The strings are varying ages. It's not like we made note of when
we got each set. Cords are probably 10 years old. They stay
indoors except for this time of year.

> My strong suspicion is you have electrical leagage somewhere - the
> lights are shorting to ground (very high resistance),

Lights can't short to "ground" cuz they're only two wire devices
(tree isn't a very good conductor when you consider the wires
tend to lay on leaves)

> the cord is
> leaking to ground (very high resistance)

Possible as its a 3 conductor extension.

> or you have a leakage
> somewhere in the house wiring/outlets.

Also possible. However, I don't consider any of those to be
LIKELY!

I.e., why would it "leak" then NOT leak a second later
(when power applied from the breaker).

And, when *hot*, not leak for 8 hours of continuous use;
not leak after being disconnected for 1 second; not leak
after being disconnected for 10 seconds; then "leak"
when disconnected for 2 minutes??

I.e., what -- other than the temperature/resistance of the
tungsten filaments -- is going to exhibit changes on the
order of "many seconds" (something greater than 10 and less
than 120)?

I wish I still had my Hi-Pot tester! :<

[bob haller]

breakers are designed to get more sensitive as they age. to prevent fires..

I spent at least 15 years repairing machines in the westinghouse vanport in beaver pa breaker plant. aa truly fascinatining place

[bob haller]

>
> [I'm comfortable working with electricity -- but in the panel,
> there's nothing between you and "sudden death" :> I'm not
> going to flip the main breaker just to make these sorts
> of breaker changes]

thats what main breakers are designed for, changing breakers in a hot panel is just plain dumb...

of course you have to reset clocks etc......

but you have to do that if your home has a power failure

[Don Y]

On 12/2/2015 9:05 PM, bob haller wrote:
>>
>> [I'm comfortable working with electricity -- but in the panel, there's
>> nothing between you and "sudden death" :> I'm not going to flip the main
>> breaker just to make these sorts of breaker changes]
>
> thats what main breakers are designed for, changing breakers in a hot panel
> is just plain dumb...

Every panel I've ever been in makes it relatively easy to change
a breaker with power on. The breakers typically clip into/onto
one bus bar or the other (or both) so the "live" circuit is
not anywhere near where you are working. Only a section of the
bus bar(s) that you will be connecting to is exposed BETWEEN
the other installed breakers. In our case, that means a slot
5/8" wide and 2+ inches deep to touch the bus bar.

The hot wire running off to the branch circuit can be connected
*before* installing a breaker or disconnected *after* the breaker
is pulled out.

By contrast, the GFCI's require a connection to the neutral
bus. In our panel, that means exposing the AC line *at* the
main breaker. Turning off the breaker gives you very little
added protection -- slip and you're toast.

> of course you have to reset clocks etc......

Generational differences? :> Sure, we'd have to reset a couple
of bedroom clocks, HiFi's, oven, microwave, etc. And, coordinate
our activities so we're not without power when we're expecting to
do something (make dinner, watch a movie, etc.)

But, that's pretty easy.

The real effort comes with the computers that are undoubtedly
running at the time of the "planned outage".

I'd have to make notes as to what I was doing on each of the
computers that were powered up, at the time (assuming they
aren't actively "doing something" that will take a fair amount
of time -- like rendering a 3D model, "make world", etc.);
examine each open application so I can return to that state
when power is eventually restored.

(I typically leave a machine exactly where it was when I was
last using it so the display reminds me as to what I was doing)

Also, shut down any network appliances or headless servers
in an orderly manner. etc.

Or, hope the batteries in each UPS are stiff enough to
carry the loads for the time you *expect* to need to swap
out the breaker.

I.e., I have to do a fair bit of planning if I want to remove
power for anything more than a few seconds (which I expect
the UPS's to always handle even when batteries are toast).

> but you have to do that if your home has a power failure

I have no control over a power failure. I *do* have control
over when -- and IF -- I remove power to do electrical
maintenance!

[Pat]

On Wed, 02 Dec 2015 20:04:37 -0700, Don Y
<blocked...@foo.invalid> wrote:

>
>I.e., why would it "leak" then NOT leak a second later
>(when power applied from the breaker).
>
>And, when *hot*, not leak for 8 hours of continuous use;
>not leak after being disconnected for 1 second; not leak
>after being disconnected for 10 seconds; then "leak"
>when disconnected for 2 minutes??
>

Let's say you have a leakage of 4 mA and the GFCI is designed to trip
at a leakage of 3 to 5 mA. At 4 mA, it may or may not trip. For
whatever reason, when first turned on, its trip point is 3 mA (within
spec) but it then rises to nearer 5 mA (still within spec). Wouldn't
that explain what you are seeing? I made up those numbers, but you
get the idea. Look for a small leakage of current from hot to ground
(or a low resistance connection from neutral to ground) that is on the
hairy edge of tripping the GFCI. As others have said, water or bugs
in one of the boxes on the line is the most likely. A neutral to
ground short in one of the boxes is also possible. Good luck. These
things are not easy to find.

Pat

[trader_4]

You do know that having 700W of incandescents on even a 15A
circuit is very common and doesn't cause breakers tripping?

[mako...@yahoo.com]

> >
> > You do know that incandescent bulbs can pull about
> > 10x the current on turn on?
>
> You do know that having 700W of incandescents on even a 15A
> circuit is very common and doesn't cause breakers tripping?

OK...Lets talk details.

I don't know the details of the inards of GFI breakers. Maybe you do.

Lets say the COLD turn on surge is 20 Amps for a short time and that alone is not enough to trip a 20 A breaker.

Lets say there is also 3 mA of leakage and the trip point for the GFI breaker is 5 mA so 3 mA alone is not enough to trip the breaker.

But what about both together? Maybe both together will trip.

I don't know if each trip point is totally seperate inside the breaker or if they somehow are added. Do you? (I'm not trying to be snooty)

I do know that a truely COLD bulb turn on draws a bigger surge then one where the bulbs have been pre warmed. It doesn't seem logical I agree, but I have seen it. You have to wait a good number of seconds for the filament to totally cool to get the full surge current.

It doesn't seem like this small diffence should be the OPs problem but at this point, who knows?

I agree with the suggestion to change to a non GFI breaker as a test to eliminate the leakage part of the question.

Mark

[trader_4]

On Thursday, December 3, 2015 at 9:04:11 AM UTC-5, mako...@yahoo.com wrote:
> > >
> > > You do know that incandescent bulbs can pull about
> > > 10x the current on turn on?
> >
> > You do know that having 700W of incandescents on even a 15A
> > circuit is very common and doesn't cause breakers tripping?
>
> OK...Lets talk details.
>
> I don't know the details of the inards of GFI breakers. Maybe you do.
>
> Lets say the COLD turn on surge is 20 Amps for a short time and that alone is not enough to trip a 20 A breaker.
>
> Lets say there is also 3 mA of leakage and the trip point for the GFI breaker is 5 mA so 3 mA alone is not enough to trip the breaker.
>
> But what about both together? Maybe both together will trip.
>
> I don't know if each trip point is totally seperate inside the breaker or if they somehow are added. Do you? (I'm not trying to be snooty)
>

Yes, they are separate. The fault current is measured by comparing the
balance between the current in the hot and neutral and it trips
independently of the overall current. Adding wouldn't get you anywhere
because the fault current trip is three orders of magnitude smaller than
the load current trip.

> I do know that a truely COLD bulb turn on draws a bigger surge then one where the bulbs have been pre warmed. It doesn't seem logical I agree, but I have seen it. You have to wait a good number of seconds for the filament to totally cool to get the full surge current.
>

I agree that cold bulbs will draw a lot more current initially.

> It doesn't seem like this small diffence should be the OPs problem but at this point, who knows?
>
> I agree with the suggestion to change to a non GFI breaker as a test to eliminate the leakage part of the question.
>
> Mark

I thought he said he had done that and it worked without tripping?

[Don Y]

On 12/3/2015 7:03 AM, mako...@yahoo.com wrote:
>
>>> You do know that incandescent bulbs can pull about 10x the current on
>>> turn on?
>>
>> You do know that having 700W of incandescents on even a 15A circuit is
>> very common and doesn't cause breakers tripping?
>
> OK...Lets talk details.
>
> I don't know the details of the inards of GFI breakers. Maybe you do.
>
> Lets say the COLD turn on surge is 20 Amps for a short time and that alone
> is not enough to trip a 20 A breaker.

We know it isn't -- because I moved the extension cord to a non-GFCI circuit
and the circuit had no problem holding the load.

(We also know that in years past, a 15A-18A load had no problem on the
same GFCI circuit!)

> Lets say there is also 3 mA of leakage and the trip point for the GFI
> breaker is 5 mA so 3 mA alone is not enough to trip the breaker.
>
> But what about both together? Maybe both together will trip.

I don't know. Clearly (?) there is something "GFCI-related" with the
current situation -- as a second GFCI breaker swapped in to replace the
original GFCI breaker is behaving exactly the same way.

> I don't know if each trip point is totally seperate inside the breaker or
> if they somehow are added. Do you? (I'm not trying to be snooty)

I don't. As I pointed out upthread, there's no guarantee that a
non-GFCI's current holding characteristics, response time, etc.
are the same as that of a GFCI breaker WITH THE GFCI PORTION DISABLED.

> I do know that a truely COLD bulb turn on draws a bigger surge then one
> where the bulbs have been pre warmed. It doesn't seem logical I agree, but
> I have seen it. You have to wait a good number of seconds for the filament
> to totally cool to get the full surge current.

Again, note the (apparently thermal) characteristics reported:
- breaker IMMEDIATELY trips when switched on with a "cold" load
(we'll leave the definition of "cold" vague, for now)
- seconds later, throwing the breaker holds, indefinitely
- "cold" lamps "plugged into" a live circuit immediately trip it
- lamps that have been on for hours can be unplugged and replugged
within 1 (or 10!) seconds and the circuit will hold
- lamps that have been allowed to "rest" for 2 minutes will immediately
trip the breaker

It sure *seems* like allowing things to "cool off" -- or, starting
with something "cold" -- is the differentiating aspect of the problem.

> It doesn't seem like this small diffence should be the OPs problem but at
> this point, who knows?
>
> I agree with the suggestion to change to a non GFI breaker as a test to
> eliminate the leakage part of the question.

Note that all this would do is isolate the "in wall wiring" as a potential
cause of an hypothesized GFCI issue. We've already tried a non-GFCI
branch circuit with the extension cord and lamps.

I'll try plugging the extension cord into a kitchen outlet (unloaded circuit)
as that would test a different GFCI with the existing extension cord
BUT DIFFERENT WIRING (as we've already tried a different GFCI with the
existing extension cord and THE SAME WIRING).

[This is easy to do whereas tying the existing wiring to a nonGFCI
breaker is a significant effort]

[Don Y]

On 12/3/2015 4:25 AM, Pat wrote:
> On Wed, 02 Dec 2015 20:04:37 -0700, Don Y
> <blocked...@foo.invalid> wrote:
>
>>
>> I.e., why would it "leak" then NOT leak a second later
>> (when power applied from the breaker).
>>
>> And, when *hot*, not leak for 8 hours of continuous use;
>> not leak after being disconnected for 1 second; not leak
>> after being disconnected for 10 seconds; then "leak"
>> when disconnected for 2 minutes??
>>
> Let's say you have a leakage of 4 mA and the GFCI is designed to trip
> at a leakage of 3 to 5 mA. At 4 mA, it may or may not trip. For
> whatever reason, when first turned on, its trip point is 3 mA (within
> spec) but it then rises to nearer 5 mA (still within spec). Wouldn't

Wait, what is "it" in each of your statements? The actual leakage
current? Or, the *setpoint* -- the point DEFINED BY THE BREAKER -- at
which the GFCI will open the circuit?

What causes it (whatever "it" may be) to rise?

> that explain what you are seeing? I made up those numbers, but you
> get the idea. Look for a small leakage of current from hot to ground
> (or a low resistance connection from neutral to ground) that is on the
> hairy edge of tripping the GFCI. As others have said, water or bugs
> in one of the boxes on the line is the most likely. A neutral to
> ground short in one of the boxes is also possible. Good luck. These
> things are not easy to find.

Ha! That last nominated for Understatement of the Year! ;-)

[mako...@yahoo.com]

On Thursday, December 3, 2015 at 9:17:11 AM UTC-5, trader_4 wrote:
> On Thursday, December 3, 2015 at 9:04:11 AM UTC-5, mako...@yahoo.com wrote:
> > > >
> > > > You do know that incandescent bulbs can pull about
> > > > 10x the current on turn on?
> > >
> > > You do know that having 700W of incandescents on even a 15A
> > > circuit is very common and doesn't cause breakers tripping?
> >
> > OK...Lets talk details.
> >
> > I don't know the details of the inards of GFI breakers. Maybe you do.
> >
> > Lets say the COLD turn on surge is 20 Amps for a short time and that alone is not enough to trip a 20 A breaker.
> >
> > Lets say there is also 3 mA of leakage and the trip point for the GFI breaker is 5 mA so 3 mA alone is not enough to trip the breaker.
> >
> > But what about both together? Maybe both together will trip.
> >
> > I don't know if each trip point is totally seperate inside the breaker or if they somehow are added. Do you? (I'm not trying to be snooty)
> >
>
> Yes, they are separate. The fault current is measured by comparing the
> balance between the current in the hot and neutral and it trips
> independently of the overall current. Adding wouldn't get you anywhere
> because the fault current trip is three orders of magnitude smaller than
> the load current trip.
>

Of course the currents are not added directly.
That is not what i meant.
5 mA is nothing compared to 20A.


I mean the trip forces in the mechanism might add.

If 19 Amps puts say 1 pound of force on the trip mechanism and 3 mA also puts one pound of force, then each alone might not trip it, but together they put 2 pounds of force which could be enough to trip it.

These are mechanical devices afterall.

Mark

[trader_4]

The GFCI isn't putting gradual force on the breaker to open it. It's
detecting when a fault current exceeds the ~6ma level and driving a
solenoid that opens the breaker. It's an all or nothing, instantaneous,
thing, not gradual.

[dpb]

On 12/03/2015 10:45 AM, Don Y wrote:
...

> We know it isn't -- because I moved the extension cord to a non-GFCI
> circuit and the circuit had no problem holding the load.

But have you done the simple expedient of swapping out extension cords yet?

...

> I'll try plugging the extension cord into a kitchen outlet (unloaded
> circuit)
> as that would test a different GFCI with the existing extension cord
> BUT DIFFERENT WIRING (as we've already tried a different GFCI with the
> existing extension cord and THE SAME WIRING).

I repeat--

But have you done the simple expedient of swapping out extension cords yet?

> [This is easy to do whereas tying the existing wiring to a nonGFCI
> breaker is a significant effort]

Just swap a standard breaker into the slot in the box.

--

[Don Y]

On 12/3/2015 11:32 AM, dpb wrote:
> On 12/03/2015 10:45 AM, Don Y wrote:

> ....

>
>> We know it isn't -- because I moved the extension cord to a non-GFCI
>> circuit and the circuit had no problem holding the load.
>
> But have you done the simple expedient of swapping out extension cords yet?

Different extension cord makes no change in symptoms.

>> I'll try plugging the extension cord into a kitchen outlet (unloaded
>> circuit)
>> as that would test a different GFCI with the existing extension cord
>> BUT DIFFERENT WIRING (as we've already tried a different GFCI with the
>> existing extension cord and THE SAME WIRING).
>
> I repeat--
>
> But have you done the simple expedient of swapping out extension cords yet?

(sigh) Sorry, but *I* can make a giant list of all possible
combinations and permutations or circuit breakers, circuit breaker
TYPES, extension cords, number of strings, WHICH strings, internal
wiring, ambient temperature, time between applications of loads,
etc. ...

then, try ALL of those variations to find the one(s) that work and
don't.

That's not troubleshooting. That's what (inept) mechanics/plumbers/PC
technicians/doctors/etc. do day to day:

"Well, let's try replacing the battery to see if that's the reason
your old battery died..."

(weeks later) "Hmmm... I guess it wasn't the battery as that NEW
one has also died! Let's try replacing the alternator!"

(weeks later) "Hmmm... what are the chances that the new/rebuilt
alternator was defective? Maybe the cable harness is bad..."

I'm looking for a *reasoned* approach to a particular cause and effect:
if *this* is the underlying problem, then this experiment will serve
to isolate and identify that as the cause.

>> [This is easy to do whereas tying the existing wiring to a nonGFCI
>> breaker is a significant effort]
>
> Just swap a standard breaker into the slot in the box.

Do you understand the difference between "a standard breaker"
and a GFCI?

A standard breaker has two connections: the power from the
distribution bus bar (usually a "snap on") and the *wire*
that feed the branch circuit ("load"). The branch circuit
picks up it's neutral and ground connections from a common
connection point shared among all branch circuits (as well as
the "AC line input")

A GFCI breaker has *four* connections: bus bar, load, NEUTRAL
and NEUTRAL PIGTAIL. I.e., the neutral wire feeding the branch
circuit connects to the breaker, NOT the neutral connection point.

Assuming you remove the GFCI and LEAVE IT DANGLING by it's
neutral pigtail, you still have to route the neutral for that
branch circuit up to the connection point for ALL the
neutral's in the panel. It's not "right next to" the breaker,
alongside the "hot" connection to the breaker!

Would you like me to also replace all of the RED lights in
the strings with BLUE ones? Maybe BOTH extensions are defective?
After all, both have been out in the same environment... maybe
they've both developed the same fault? A fault that HEALS
ITSELF when the lights have had a chance to warm up??

Maybe both GFCI breakers have failed in the same way -- despite
the fact that the other three located within inches haven't?

Sorry, I don't mean to sound pissy but "try this" is not what
I'm looking for. I want to approach the problem logically
not willy-nilly. I'd hoped someone might have *definitive*
information of problems like this instead of a litany of
hit-or-miss attempts. I.e., an explanation that reconciles
ALL of the observations I've posted.

(sigh)

[mako...@yahoo.com]

> >
> > I repeat--
> >
> > But have you done the simple expedient of swapping out extension cords yet?
>
> (sigh) Sorry, but *I* can make a giant list of all possible
> combinations and permutations or circuit breakers, circuit breaker
> TYPES, extension cords, number of strings, WHICH strings, internal
> wiring, ambient temperature, time between applications of loads,
> etc. ...
>
> then, try ALL of those variations to find the one(s) that work and
> don't.
>
> That's not troubleshooting. That's what (inept) mechanics/plumbers/PC
> technicians/doctors/etc. do day to day:
>

sorry but that is a part of troubleshooting
Swapping around parts that you already have can be a very efficeint troubleshooting technique.

If we told you to go out and buy all new lights and new extension cords and new breakers and replace them all, that would not be troubleshooting, that would be shot-gunning.


If you prefer a more analytical approach, then go out and buy a dual trace oscilloscope, clamp on current probe and other assorted test equipment and we get then gather enough data to decide exactly what the problem is without swapping parts.


Sounds like we have nothing more to offer you in the way of help.

Be sure to come back and let us know what the answer turns out to be.

Mark

[dpb]

On 12/03/2015 1:21 PM, Don Y wrote:
...

> Sorry, I don't mean to sound pissy but "try this" is not what
> I'm looking for. I want to approach the problem logically
> not willy-nilly. I'd hoped someone might have *definitive*
> information of problems like this instead of a litany of
> hit-or-miss attempts. I.e., an explanation that reconciles
> ALL of the observations I've posted.
>
> (sigh)

One quick one is the possibility of the extension cord having a fault
(particularly as noted, if it's one of the pretty-common type with the
indicator light in the plug). It's a common element in all the
combinations done to date and is simple as compared to many of the other
things you've tried already or proposing to eliminate.

"Willy-nilly" is pretty much what you've done to date; the above is, as
noted, one common element in all. It may _not_ have any bearing but
then again, if it just turned out to be so, then all the other
pontificating is of little value.

(PS) And, no, on the GFCI circuit breaker I'm not specifically aware --
don't have any and plan to live out my life that way. :) If it's not
feasible, then ok, so be it.

--

[Don Y]

On 12/3/2015 12:36 PM, mako...@yahoo.com wrote:
>
>>>
>>> I repeat--
>>>
>>> But have you done the simple expedient of swapping out extension cords
>>> yet?
>>
>> (sigh) Sorry, but *I* can make a giant list of all possible combinations
>> and permutations or circuit breakers, circuit breaker TYPES, extension
>> cords, number of strings, WHICH strings, internal wiring, ambient
>> temperature, time between applications of loads, etc. ...
>>
>> then, try ALL of those variations to find the one(s) that work and don't.
>>
>> That's not troubleshooting. That's what (inept) mechanics/plumbers/PC
>> technicians/doctors/etc. do day to day:
>
> sorry but that is a part of troubleshooting Swapping around parts that you
> already have can be a very efficeint troubleshooting technique.

No, that's the lazy approach. That's the way auto mechanics start swapping
things (charging you for each "new replacement" -- even if it didn't FIX
the problem) out until they stumble on the "solution". Do they ever
work their way backwards, undoing all of the other (faulty) changes
they introduced along the way to definitively identify/verify that the
"final change" was, in fact, the real reason? Do they swap the "bad"
part back in to verify that the problem manifests, again?

This is just a lack of deductive reasoning capability. I see it in
how folks troubleshoot electronic designs, software, etc. all the time.
"Let's try this..." Then, if the device/program *appears* to work,
they content themselves with having "fixed it" -- with no basis for
belief that it is, in fact, (permanently/actually) "fixed".

"Well, it's working NOW..."

I guess in grade school we were taught "The Scientific Method"; form
an hypothesis, construct an experiment to test that hypothesis, then
apply it and verify the results.

And, you can run that process forwards or backwards, with predictable
outcomes in each case.

E.g., note that when I unplugged the lamps this morning and re-plugged
them, they didn't trip the breaker. Yet, plugging them "cold" caused
an instant trip. So, modify the experiment -- wait *10* seconds
before re-plugging. Then, 2 minutes.

Ah, now I have new information to assist in formulating a theory
(what, in the circuit, can "account for time"?)

> If we told you to go out and buy all new lights and new extension cords and
> new breakers and replace them all, that would not be troubleshooting, that
> would be shot-gunning.
>
> If you prefer a more analytical approach, then go out and buy a dual trace
> oscilloscope, clamp on current probe and other assorted test equipment and
> we get then gather enough data to decide exactly what the problem is without
> swapping parts.

You'll note I lamented the loss of my HiPot tester, up-thread??

> Sounds like we have nothing more to offer you in the way of help.

Agreed. I'll return to my original plan of diagnosis.

> Be sure to come back and let us know what the answer turns out to be.

I'll look into it this weekend. The lights won't be needed, again, for
several days so I can spend my time on other things that are more pressing.

[Don Y]

On 12/3/2015 12:44 PM, dpb wrote:
> On 12/03/2015 1:21 PM, Don Y wrote:

> ....

>
>> Sorry, I don't mean to sound pissy but "try this" is not what
>> I'm looking for. I want to approach the problem logically
>> not willy-nilly. I'd hoped someone might have *definitive*
>> information of problems like this instead of a litany of
>> hit-or-miss attempts. I.e., an explanation that reconciles
>> ALL of the observations I've posted.
>>
>> (sigh)
>
> One quick one is the possibility of the extension cord having a fault
> (particularly as noted, if it's one of the pretty-common type with the
> indicator light in the plug). It's a common element in all the combinations
> done to date and is simple as compared to many of the other things you've tried
> already or proposing to eliminate.

But, it has to be a "leak" -- as the problem doesn't manifest when
plugged into a non-GFCI circuit.

And, that "leak" has to somehow be healing itself, then reappearing
(based on whether or not the lights have been on or off and for how
long!)

> "Willy-nilly" is pretty much what you've done to date; the above is, as noted,
> one common element in all. It may _not_ have any bearing but then again, if it
> just turned out to be so, then all the other pontificating is of little value.

I've been "willy nilly" in an attempt to be polite to folks offering
suggestions here. It's not how *I* would have tackled the problem.
But, having asked, it would be rude to dismiss suggestions when
(in MOST cases -- change breaker, change load, plug into different
outlet, swap extension cord, etc.) I can just do the test to humor
the respondent.

But, the "try this" can go on indefinitely. And, you can always
rationalize a semi-legitimate justification for each such attempt!
(e.g., ALL of the lamps have been out in the elements; perhaps
they've *all* been affected in some way! So, it doesn't matter
which strings you try, the problem will persist -- cuz it's
in ALL of them!)

[I worked on a piece of test equipment many years ago. There was
a short between two of the power supplies -- on a "circuit board"
that was 2 ft wide, 6 feet long and contained *thousands* of
components! I.e., the short could be in any of those components.
Or, in the board, itself. Troubleshooting all those potential
connections -- considering that the short was an UNINTENDED
connection -- would be a daunting task. Better to replace the
board and start over... after several months of delay!

I hypothesized that a capacitor could be the "short" -- they were
all over the (brand new!) board. Of course, *which* capacitor
was the problem!

So, I simply picked one AT RANDOM, removed it from the circuit
and tested it.

Shorted!

My colleagues looked at me like I had just walked on water:
not only had I come up with the "problem" but also managed to
find the defective capacitor, on my first attempt!

Boss, quickly turned that optimism into an accusation: "There's
no way you could have known that THAT capacitor was the failed
device! You *put* that there!!"

<frown> Sort of unfair -- given that I'd just saved his *ss!

I came back later to be greeted by news that *all* of the capacitors
were shorted! (WTF??) Turned out, the board manufacturer had
installed capacitors with the wrong voltage rating and, as soon as
we had applied power, they all went "pffft!"

So, there was no "luck" involved in my finding THE shorted capacitor.
OTOH, there was *genius* in my REASONING that it could be *a*
shorted capacitor -- and not a wire that was misplaced (of the
tens of thousands on the board)!]

> (PS) And, no, on the GFCI circuit breaker I'm not specifically aware -- don't
> have any and plan to live out my life that way. :) If it's not feasible, then
> ok, so be it.

My problem *has* to be related to the GFCI characteristics of the "circuit".
And, not the GFCI detection itself (faulty breaker) but, rather, some
aspect of what it is testing that the current configuration happens
to "tickle" -- and, only in those cases where it *does* tickle (also
accounting for those cases where it *doesn't*!)

[dpb]

On 12/03/2015 3:08 PM, Don Y wrote:
...

> E.g., note that when I unplugged the lamps this morning and re-plugged
> them, they didn't trip the breaker. Yet, plugging them "cold" caused
> an instant trip. So, modify the experiment -- wait *10* seconds
> before re-plugging. Then, 2 minutes.
>
> Ah, now I have new information to assist in formulating a theory
> (what, in the circuit, can "account for time"?)

A thermal effect as postulated previously.

...

> Agreed. I'll return to my original plan of diagnosis.
>

...

_IF_ you did still have high quality test gear, I'd tend to agree with
your attempt at more esoteric trouble-shooting. Lacking that, the
likelihood of placing a measurement at the right spot with the facility
to catch the event is approaching zero...

So you might as well eliminate the one common component from the problem
before continuing down all those various ratholes you've previously
enumerated...

--

[cl...@snyder.on.ca]

On my QO panel it's easy - neutral buss on both sides. Putting in the
GFCI I had to extend the neutral because the sparky that replaced the
panel didn't run the neutrals for the breakers on the one side to the
same side as the breaker - he put all the neutrals on the "short"
side. VERY neet job - but made it difficult to install GFCI breakers
in the panel.

[cl...@snyder.on.ca]

Just wondered with 12G - so they are 20 amp circuits - - -

[cl...@snyder.on.ca]

Bolt on or snap on? I've seen a lot of issues lately on the old CH
panels - (I'm talking from the '70s) - failing breakers and no direct
replacements - so guys put in the new ones and butcher the panel cover
to make them fit.

[Don Y]

On 12/3/2015 2:26 PM, dpb wrote:
> On 12/03/2015 3:08 PM, Don Y wrote:

> ....

>
>> E.g., note that when I unplugged the lamps this morning and re-plugged
>> them, they didn't trip the breaker. Yet, plugging them "cold" caused
>> an instant trip. So, modify the experiment -- wait *10* seconds
>> before re-plugging. Then, 2 minutes.
>>
>> Ah, now I have new information to assist in formulating a theory
>> (what, in the circuit, can "account for time"?)
>
> A thermal effect as postulated previously.
>

> ....

>
>> Agreed. I'll return to my original plan of diagnosis.
>>

> ....

>
> _IF_ you did still have high quality test gear, I'd tend to agree with your
> attempt at more esoteric trouble-shooting. Lacking that, the likelihood of
> placing a measurement at the right spot with the facility to catch the event is
> approaching zero...
>
> So you might as well eliminate the one common component from the problem before
> continuing down all those various ratholes you've previously enumerated...

No, the logical approach is to imagine some agency (weather, infestation,
phase of the moon) that has asserted itself on the "system". Then,
think of what sorts of "changes" it could have made THAT WERE NOT
PRESENT, PREVIOUSLY.

E.g., leaf cutter wasps laying eggs *inside* receptacles -- given that
I know these exist, here; water infiltrating a fixture (nope, no water
sources); something chewing on insulation (unlikely); etc.

I.e., look for a simple explanation that ties all the observations
together, consistently. Yeah, it could be all my bulbs have
a problem; it could be all my extension cords; all my GFCI's;
etc. But, it's not LIKELY that all that stuff happened AT THE
SAME TIME. I'd buy it if I had a problem with one string
of lights last year, another the year before, etc.

OTOH, something affecting *one* of the receptacles would make
sense -- *if* a reason for the other observations ALSO made
sense!

[cl...@snyder.on.ca]

On Wed, 02 Dec 2015 20:04:37 -0700, Don Y
<blocked...@foo.invalid> wrote:

>On 12/2/2015 7:54 PM, cl...@snyder.on.ca wrote:
>
>> I think you can pretty definitevly rule out tripping from the load of
>> the lights - cold surge or not.
>> How old are the light strings? Or the extension cords?
>
>The strings are varying ages. It's not like we made note of when
>we got each set. Cords are probably 10 years old. They stay
>indoors except for this time of year.
>
>> My strong suspicion is you have electrical leagage somewhere - the
>> lights are shorting to ground (very high resistance),
>
>Lights can't short to "ground" cuz they're only two wire devices
>(tree isn't a very good conductor when you consider the wires
>tend to lay on leaves)

Leakge from deteriorated insulation to the leaves is all it takes to
trip a GFCI - and the fact they "stick" on the second or third attempt
means they could be just drying themselves out enough to reduce the
leak enough to not trip the third time.
>
a 5ma leak is low enough you generally will not even feel it if you
are holding the wire and causing the "leak"

[cl...@snyder.on.ca]

On Wed, 2 Dec 2015 20:05:12 -0800 (PST), bob haller <hal...@aol.com>
wrote:

On a square D QO panel you'd have to be pretty stupid to shock
yourself changing a breaker with the panel "live". Like you'd almost
have to TRY.

[cl...@snyder.on.ca]

If it's the "Old CH" I'm thinking of, I'd be replacing it. It
wouldn't stand a chance of passing code up here as a new install. NO
conductors from the "switched" side are allowed into the "main" side
of the panel. None. Period.

[Don Y]

Meter center has KWHr meter and mains input on left side
(power feeds from below grade). Right side is just a
"load center".

Two bus bars run the length (height) of the panel, interleaving
the two "hot legs" (i.e., a double wide breaker ends up straddling
both legs).

Bus bars have large "tongues" that protrude at right angles above
the bars. Underside of breakers have a tight slot that grabs onto
this tongue. (other "end" of breaker has a lip that clips over
a metal/grounded mechanical support).

So, lift side of breaker that adheres to the tongue, pivoting on
the other side that is clipped behind that metal lip. Breaker
is then free to be removed -- save for any conductors that
are tied to it (e.g., neutral pigtail, neutral load and hot
load for GFCI; hot load for regular breaker)

Panel is at least 35 years old (so, I've been chasing down
NOS spares before they become unobtanium). But, everything is
still intact.

The GFCI's were purchased "new" many years ago. Note that
there are 5 in the panel; three of which see everyday use
(kitchen countertops plus bathrooms) and have never complained
(despite large loads -- toaster oven, electric frying pan,
hair dryers, etc.).

Fourth GFCI has just been "stored" in the panel. It was the
candidate that I exploited to replace the GFCI for this
outlet branch circuit.

I.e., too many coincidences wouold have to occur for me
to conclude it was a GFCI (*breaker*) problem.

<shrug> I'll look at it this weekend. I've got some candy
that I've got to make, today (while SWMBO is "away")

[cl...@snyder.on.ca]

What GFCI breakers are you using in that "old ch" panel??

Are they listed for the panel? If it is an "old ch" panel the GFCIs
were not original install - correct? or is it not that "old" a CH
panel?

[cl...@snyder.on.ca]

On the Square D the 2 trip mechanisms are totally separate, and the
GFCI load section is the same as the non GFCI breaker. No idea what
breakers you have in the CH panel, but "generally" that is how they
are made.

[dpb]

On 12/03/2015 3:20 PM, Don Y wrote:
...

> My problem *has* to be related to the GFCI characteristics of the
> "circuit".
> And, not the GFCI detection itself (faulty breaker) but, rather, some
> aspect of what it is testing that the current configuration happens
> to "tickle" -- and, only in those cases where it *does* tickle (also
> accounting for those cases where it *doesn't*!)

Agreed, and all I'm suggesting doing is eliminating one possible source
for that place...it could be there's a damaged area but not drastically
such that it's visibly obvious that's let some moisture in and after a
short time it "bakes" it out locally to the point the problem isn't
apparent. But, as you've demonstrated, when it is off for any period of
time, there's enough inside there to recreate the leakage path.

Now, granted, it's possible it's in one of these other locations but
again, it seems silly and the _most_ time-consuming and least likely to
reach nirvana quickest to start down all of the various other components
looking for the case when there's still one common component that hasn't
been yet eliminated. (Unless, of course, you just happen to be lucky
and it's the first one you try, but that is again back to the luck of
the draw, nothing you've done via "scientific method". At least I'm
starting with a common cause location.

(Besides, just think how much fun you'll have when you can say "I told
you so!!!!")

--

[Don Y]

On 12/3/2015 2:33 PM, cl...@snyder.on.ca wrote:

> On my QO panel it's easy - neutral buss on both sides. Putting in the
> GFCI I had to extend the neutral because the sparky that replaced the
> panel didn't run the neutrals for the breakers on the one side to the
> same side as the breaker - he put all the neutrals on the "short"
> side. VERY neet job - but made it difficult to install GFCI breakers
> in the panel.

In our case, the ground/neutral bus is located on the meter side of
the panel. I.e., to gain access, you have to expose the AC mains
on the output of the meter connection/input to main disconnect/output
of main disconnect.

Of course, the bus bar is mounted against the rear of the panel,
so you have to reach *into* the panel (with screwdriver) to open
the lockdown screws in the bar. Then, reach in with your *fingers*
to thread the neutral wire (or, neutral pigtail!) under the
lockdown screw -- before tightening it.

So, all of the GFCI's must be located at the top of the loadcenter
side of the panel -- else their pigtails won't reach the grounding
bar! And, all the neutrals have to work their way up to the top
of the box where they can cross over to the meter side to tie into
the ground *and* neutral!

I.e., I don't like opening that side of the box! :>

You can replace a breaker just by prying the "tongue" side loose.
Then, with the breaker IN YOUR HAND, you can leisurely remove the
hot conductor from it! (and neutral, if a GFCI). You don't have to
make any penetration into the box (and the bus bars waiting there!)

OTOH, if you opt to replace a GFCI with a non-GFCI, you now have
to figure out how to get the branch circuit's neutral over
to the meter side of the box!

(and, if you're only doing this to test a theory, you look for
other ways to garner that information that are less involved! :> )

[Don Y]

Yes. Code requires them for kitchen countertop. etc. So, I
just installed a bunch of them (bathrooms, countertops, outdoor
and garage)

[Don Y]

CH GFCI's for this particular panel. Did my homework when I
bought them. Hard to find cuz the panel is old -- can't just
walk into a Lowe's/Home Despot and pick them up!

Took advantage of a contractor friend's discount to buy them
from an (overpriced) electrical supply house, locally.

[Mark Lloyd]

[snip]

> So, "two strings of three". Each string has 25 (?) 9W (nominal) lamps
> so ~225W/string or 675W per string-of-3; 1350W for the pair of these.

C9 lights? The 9 is the size of the bulb (I think 9mm across). IIRC
power consumption is 7W.

[snip]

--
22 days until the winter celebration (Friday December 25, 2015 12:00:00
AM for 1 day).

Mark Lloyd
http://notstupid.us/

"The man who wants to be an angel is never in a hurry to begin." [Lemuel
K. Washburn, _Is The Bible Worth Reading And Other Essays_]

[Don Y]

On 12/3/2015 3:12 PM, Mark Lloyd wrote:
>
> [snip]
>
>> So, "two strings of three". Each string has 25 (?) 9W (nominal) lamps
>> so ~225W/string or 675W per string-of-3; 1350W for the pair of these.
>
> C9 lights? The 9 is the size of the bulb (I think 9mm across). IIRC power
> consumption is 7W.

Dunno. The "9" stuck in my mind. They are the "really big" incandescents
(not to be confused with the smaller 4W and 7W (identical to the 4W
in size) "night lights" you'd encounter in a house.

[I don't have any spare bulbs in store-bought packages; and the actual
strings get stored in shoebox sized boxes (that aren't actually for
shoes) cuz it's impractical to try to cram them back into the
boxes in which they originally were purchased).]

For other incandescents, often the wattage is stamped in the metal
screw base. I should see if I can read anything (that small) there...

[John G]

> The outlets in the back of the house are on a 20A GFCI.
> (Note to self: are there any other outlets on that same
> circuit that I need to chase down?)
>
> Presently using them to light XMAS lights on one of the
> citrus trees. IIRC, each string is about 250W. With
> ~700W on the circuit, turning the breaker ON (i.e., using
> it as a switch -- instead of plugging/unplugging the
> load) causes it to immediately trip. Repeating the
> action in short order appears to get it to latch and
> remain latched (ON), indefinitely.
>
> OK, so the surge when all the lamps are cold can increase
> the inrush current -- on the short term -- to levels that
> probably exceed the 20A limit of the breaker.
>
> "In theory"
>
> OTOH, in years past, I've run the circuit at close to its
> capacity (~10 strings) without this problem.
>
> I've changed breakers (swapped with one feeding another
> circuit) and the problem persists.
>
> [There are no leakage paths in the wiring OUTSIDE]
>
> This suggests something in the wiring/fixtures. I'll
> start isolating outlets, tomorrow (dark here, now).
> Perhaps some insect (leaf cutter?) has opted to nest
> in one of the receptacles.
>
> Anything else I should explore?


Many many years ago I worked as an electrician in a hospital that had an indoor pool. Every day when the attendant turned on the Metal Halide HID overhead lights over the pool deck, the GFCI circuit breakers would trip. I changed the breakers and tighten the connections, but the symptoms never went away. When the circuit breakers were reset, the lights stayed on until the pool closed when they were then intentionally shut off. The next day would bring the same symptoms. I had surmised that perhaps the high humidity environment was causing condensation on the ballasts, but that was just a best guess. After a while I gave up and just made it my business to turn on the pool lights every day.

John Grabowski
http://www.MrElectrician.TV

[gfre...@aol.com]

On Thu, 03 Dec 2015 14:08:34 -0700, Don Y
<blocked...@foo.invalid> wrote:

>No, that's the lazy approach. That's the way auto mechanics start swapping
>things (charging you for each "new replacement" -- even if it didn't FIX
>the problem) out until they stumble on the "solution".

Since you are not paying for things you try that is not really a good
analogy but without the right test equipment, eliminating things in
the path is probably the only real way to go.

If I was really willing to "diagnose" this I would get a device type
GFCI, Disable the trip mechanism and look at the output of the
differential amplifier with a scope as I plugged in the lights, cords
etc looking for the one that is the offender. You could calibrate your
result using a pot and introducing a known fault value.
My bet is you will see this thing cruising in the 3-4 ma range so any
little glitch pushes it over.

[trader_4]

On Thursday, December 3, 2015 at 7:47:53 PM UTC-5, gfre...@aol.com wrote:
> On Thu, 03 Dec 2015 14:08:34 -0700, Don Y
> <blocked...@foo.invalid> wrote:
>
> >No, that's the lazy approach. That's the way auto mechanics start swapping
> >things (charging you for each "new replacement" -- even if it didn't FIX
> >the problem) out until they stumble on the "solution".
>
> Since you are not paying for things you try that is not really a good
> analogy but without the right test equipment, eliminating things in
> the path is probably the only real way to go.
>

I always start on the path of trying to fully diagnose the problem
instead of swapping parts. But anyone who has worked on cars has sure
had many times where they wished they had the dealers stock of parts
to try swapping something that is easily swappable to see if it fixes it.

> If I was really willing to "diagnose" this I would get a device type
> GFCI, Disable the trip mechanism and look at the output of the
> differential amplifier with a scope as I plugged in the lights, cords
> etc looking for the one that is the offender. You could calibrate your
> result using a pot and introducing a known fault value.
> My bet is you will see this thing cruising in the 3-4 ma range so any
> little glitch pushes it over.

Agree, that's the problem and why you're left with swapping. To conduct
the required tests is going to require some advanced gear that homeowner's
typically don't have. Even if I had it or had access to it, I wouldn't
waste my time trying to figure it out.

[Don Y]

In addition to the expense and inconvenience, that opens up a whole
can of worms. House is block so you can't move the box "an inch
or two" to accommodate breakers in the new loadcenter being some
different distance from where the wires come through the block.

Neighbor enhanced his service some years ago. A nightmare for
him to "stretch" the wires to reach the new locations of the
breakers. You roll the dice; if the wires don't reach, you're
SoL (have to rerun the branch circuit).

Another neighbor had his panel catch fire (corroded mains).
Same sort of issue -- can't just find "drop in" replacements
for these sorts of things! (And, you're without power
for the time it takes to tear down, install, rewire AND
get inspected!)

"If it ain't broke, don't fix it!"

[Don Y]

"Stupid" may be a bit harsh. But, if you're not doing this sort of
thing on a daily basis, it's easy to get focused on WHAT you are
trying to do and forget HOW you should be doing it!!

When I was in school, I had to make some wiring changes to a
friend's vehicle. Had soldering station sitting out on his
vehicle (hood or trunk, I can't recall).

Realized the tip I was using was too small to convey enough heat to
the work. Not keen on waiting for it to cool off...

Didn't have a rag handy to grasp it...

So, lifted my leg to use the fabric of my jeans (down by my ankle)
to grab the tip and unscrew it. Then, holding the tip in my
pant leg, lifted my ankle even higher to drop the (hot!) tip
on the bumper. Set my leg back down -- tickled that I'd managed
to do this without falling over -- and promptly picked up the tip
with my right hand to place it in my *pocket*!

Of course, it never made it *to* my pocket. The sound of searing flesh
was unmistakeable.

My buddy just looked at me and said, "I can't believe -- after that
elaborate *dance* that you just did (to avoid touching the hot
tip) -- that you just grabbed that!"

<shrug> Too preoccupied with trying NOT to fall over that I'd
forgotten WHY this had been necessary! :<

[Don Y]

On 12/3/2015 2:39 PM, cl...@snyder.on.ca wrote:
> On Wed, 02 Dec 2015 20:04:37 -0700, Don Y
> <blocked...@foo.invalid> wrote:
>
>> On 12/2/2015 7:54 PM, cl...@snyder.on.ca wrote:
>>
>>> I think you can pretty definitevly rule out tripping from the load of
>>> the lights - cold surge or not.
>>> How old are the light strings? Or the extension cords?
>>
>> The strings are varying ages. It's not like we made note of when
>> we got each set. Cords are probably 10 years old. They stay
>> indoors except for this time of year.
>>
>>> My strong suspicion is you have electrical leagage somewhere - the
>>> lights are shorting to ground (very high resistance),
>>
>> Lights can't short to "ground" cuz they're only two wire devices
>> (tree isn't a very good conductor when you consider the wires
>> tend to lay on leaves)
>
> Leakge from deteriorated insulation to the leaves is all it takes to
> trip a GFCI - and the fact they "stick" on the second or third attempt
> means they could be just drying themselves out enough to reduce the
> leak enough to not trip the third time.

Wouldn't explain why the other strings (alternate test load)
tripped the breaker. They weren't *in* the tree.

Also wouldn't account for SWMBO's comment that *she* had had
problem using the toaster oven on that circuit some months before.

"On grumbling about this ("yet another chore on my list") to
SWMBO, she claims she took the toaster oven outdoors some months
ago (WTF?) to "prepare" something and it wouldn't work, either."

[Don Y]

On 12/3/2015 5:18 PM, John G wrote:

> Many many years ago I worked as an electrician in a hospital that had an
> indoor pool. Every day when the attendant turned on the Metal Halide HID
> overhead lights over the pool deck, the GFCI circuit breakers would trip. I

You haven't explicitly said it (and, as I suspect they are considerably
ABOVE the pool, it might not be required?) but were teh HID's the load
that the GFCI(s) were protecting? Or, were there other GFCI circuits
and the "noise" (?) from the HID's interfering with them?

> changed the breakers and tighten the connections, but the symptoms never
> went away. When the circuit breakers were reset, the lights stayed on until
> the pool closed when they were then intentionally shut off. The next day

So, that's the same behavior I'm reporting? I.e., first ("cold") attempt
to turn on causes breaker to trip (i.e., before it ever latches!). But,
immediately thereafter, a subsequent attempt to turn on works properly?

> would bring the same symptoms. I had surmised that perhaps the high humidity
> environment was causing condensation on the ballasts, but that was just a

How soon after the first failure would you reattempt? Would it seem
logical that any condensate would/could evaporate in that time?
(i.e., not liquid water, perhaps, but "dampness"?)

> best guess. After a while I gave up and just made it my business to turn on
> the pool lights every day.

I will return to a more structure testing "program" this weekend
(assuming nothing else rises to the top of the Honey-Do's). Among
other things, I'd like to know if, once "holding", the crcuit
will actually hold its full rated load. Or, if there is yet
another set of symptoms to add to the list...

[cl...@snyder.on.ca]

On Thu, 03 Dec 2015 15:00:23 -0700, Don Y

Lots of scrounging - lots of fun.

[cl...@snyder.on.ca]

On Thu, 03 Dec 2015 18:17:46 -0700, Don Y
<blocked...@foo.invalid> wrote:


>> If it's the "Old CH" I'm thinking of, I'd be replacing it. It
>> wouldn't stand a chance of passing code up here as a new install. NO
>> conductors from the "switched" side are allowed into the "main" side
>> of the panel. None. Period.
>
>In addition to the expense and inconvenience, that opens up a whole
>can of worms. House is block so you can't move the box "an inch
>or two" to accommodate breakers in the new loadcenter being some
>different distance from where the wires come through the block.
>

That's where you have to do your homework. I made sure the panel I
purchased would fit. A few applications of the greenley punch - I
didn't have to move a single wire - and all the wires were long enough
to reach, after sorting out what went where.

If I had let the electrician supply the panel he usually uses there
would have been a few junction boxes involved - and that I did NOT
want!!!!

>Neighbor enhanced his service some years ago. A nightmare for
>him to "stretch" the wires to reach the new locations of the
>breakers. You roll the dice; if the wires don't reach, you're
>SoL (have to rerun the branch circuit).

Or install a "stretcher box" - a surface mounted junction box to
splice the wires. Nasty - but it works, passes code, and is not
difficult.

>
>Another neighbor had his panel catch fire (corroded mains).
>Same sort of issue -- can't just find "drop in" replacements
>for these sorts of things! (And, you're without power
>for the time it takes to tear down, install, rewire AND
>get inspected!)
>
>"If it ain't broke, don't fix it!"

This is where I differ. I say fix it while it is fixable - and on your
schedule. Letting the panel decide when it has to be replaced never
works out in your favour.

[cl...@snyder.on.ca]

On Thu, 03 Dec 2015 18:25:34 -0700, Don Y
<blocked...@foo.invalid> wrote:

>On 12/3/2015 2:40 PM, cl...@snyder.on.ca wrote:
>> On Wed, 2 Dec 2015 20:05:12 -0800 (PST), bob haller <hal...@aol.com>
>> wrote:
>>
>>>> [I'm comfortable working with electricity -- but in the panel,
>>>> there's nothing between you and "sudden death" :> I'm not
>>>> going to flip the main breaker just to make these sorts
>>>> of breaker changes]
>>>
>>> thats what main breakers are designed for, changing breakers in a hot panel is just plain dumb...
>>>
>>> of course you have to reset clocks etc......
>>>
>>> but you have to do that if your home has a power failure
>> On a square D QO panel you'd have to be pretty stupid to shock
>> yourself changing a breaker with the panel "live". Like you'd almost
>> have to TRY.
>
>"Stupid" may be a bit harsh. But, if you're not doing this sort of
>thing on a daily basis, it's easy to get focused on WHAT you are
>trying to do and forget HOW you should be doing it!!

The QO panel has a "sheilded" bus - you need to stick your finger in
to touch it - I'll stick with "stupid" - or "extremely careless" -
which when working around electricity IS "stupid"

[gfre...@aol.com]

On Thu, 3 Dec 2015 17:16:03 -0800 (PST), trader_4
<tra...@optonline.net> wrote:

>On Thursday, December 3, 2015 at 7:47:53 PM UTC-5, gfre...@aol.com wrote:
>> On Thu, 03 Dec 2015 14:08:34 -0700, Don Y
>> <blocked...@foo.invalid> wrote:
>>
>> >No, that's the lazy approach. That's the way auto mechanics start swapping
>> >things (charging you for each "new replacement" -- even if it didn't FIX
>> >the problem) out until they stumble on the "solution".
>>
>> Since you are not paying for things you try that is not really a good
>> analogy but without the right test equipment, eliminating things in
>> the path is probably the only real way to go.
>>
>
>I always start on the path of trying to fully diagnose the problem
>instead of swapping parts. But anyone who has worked on cars has sure
>had many times where they wished they had the dealers stock of parts
>to try swapping something that is easily swappable to see if it fixes it.
>

When I was fixing things for a living, my first question on a support
call was asking the guy who was working on it "Can you draw a circle
around the problem"? (in an acre of computer room floor, that may not
be as simple as it sounds)

Until you know for sure what box is failing, you really have to back
up and reassess.

It was surprising how many times that just getting your head put of
the box, turned a light on and got you on the right track.
Isolating the problem does not mean simply throwing parts at it. You
should learn something at each step.

In Don's situation,. I would start with a configuration that doesn't
fail and keep adding stuff until you break it.
Drag a known good space heater or heat gun out to the end of that
extension cord and try that, bearing in mind, the fault could be on
the neutral and that will not fail without a load.